41 lines
1.1 KiB
C++
41 lines
1.1 KiB
C++
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// Copyright (C) 2009-2012 Lorenzo Caminiti
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// Distributed under the Boost Software License, Version 1.0
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// (see accompanying file LICENSE_1_0.txt or a copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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// Home at http://www.boost.org/libs/local_function
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#include <boost/phoenix/core.hpp>
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#include <boost/phoenix/function.hpp>
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#include <boost/detail/lightweight_test.hpp>
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//[phoenix_factorial
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struct factorial_impl { // Phoenix function from global functor.
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template<typename Sig>
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struct result;
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template<typename This, typename Arg>
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struct result<This (Arg)> : result<This (Arg const&)> {};
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template<typename This, typename Arg>
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struct result<This (Arg&)> { typedef Arg type; };
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template<typename Arg> // Polymorphic.
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Arg operator()(Arg n) const {
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return (n <= 0) ? 1 : n * (*this)(n - 1);
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}
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};
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int main(void) {
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using boost::phoenix::arg_names::arg1;
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boost::phoenix::function<factorial_impl> factorial;
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int i = 4;
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BOOST_TEST(factorial(i)() == 24); // Call.
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BOOST_TEST(factorial(arg1)(i) == 24); // Lazy call.
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return boost::report_errors();
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}
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//]
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